Apparatus for detinning tin-scrap.



M. LEITGH.

APPARATUS FOR DETINNING TIN SCRAP.

APPLICATION rum) FEB. 28, 1907.

906,726. Patented Dec. 15,1908.

if s snnnrs-snnm 1.

( m cc I Noz- M. LEITCH.

APPARATUS FOR DETINNING TIN SCRAP.

APPLICATION 11.21 FEB. 28, 1907.

Patented Dec. 15, 1908.

3 SEEBTS-SHEET M. LEITOH.

APPARATUS FOR DETINNING TIN SCRAP.

APPLICATION FILED FEB. 28, 1907.

Patented-Dec. 15, 1908 3 SHEETSSHBET Hogan PATENT OlTlFlliOE.

MEREDlTH LElTOH, OF ELIZABETH, NEW JERSEY, ASSIGNOR, BY MESNE ASSlGNMENTS, TO METAL PROCESS COMPANY, A CORPORATION OF NEW YORK.

APPARATUS FOR DETINNING TIN-SCRAP.

no. scopes.

To all whom iii/ray concern:

Be it known that I, lilnnnnrrn linrrcins-citizen'or" the United States, residing at Elizabeth, county of Union, State of New Jersey, hove invented cert-sin new and use- "ul Improvements in Appcrstus for Detinning M Lin-Scrap, oi' wnich the following is a full, clear, and exact desi'n-iption.

My invention relates to improvements in eppurn-tus for detinningr tin scrap and has for its object to produce-on apparatus whereby the detinning can be carried on more enoeditiously their heretofore and bettr resii ts obtained. 1

.l't further has for its object to provide an apparatus in which the internal parts can be easily insoected from time to time, it "being desirable to inspect all ports at least once in every twenty-four hours.

It further has for its object to produce an epperstus in which all the elcctricnl connections can be made pernmnent without interfering with such inspection or the removal of the deposit from the cathodes.

it further hes for its object to reduce the size and also the expense of the apparatus of a given capacity and to provide :1 convenient means for removing the deposit on the cathodes, end to secure other, ndvnn teges hereafter described, and particularly pointed out in the chums.

' l fy present invention is an improvement upon the invention disclosed in my application, Seriel No. 301,585, liled February 17,1906.

In the apparatus of my prior application, a. stationary basket for containing the tin scrap and a stationary tank for containing the electrolyte were provided, the cathodes being raised out of the electrolyte for cleansing. The stationary tank i surrounding the stationary basket mode it practically impossible to examine the basket critically, and very often wires or pieces of scrap would protrude through the orifices oi the basket, so as to make contact with the cathodes and thereby establish at short circuit. Furthermore, the basket became covered with slime and droppings from the plates and could not be thoroughly cleansed. Furthermore the drops from the plates remained in the bottom of the tank, which could not be easily emptied. Furthermore the electrical, connections between the bus- ,35. bsrsend the csthodescouldnotlpe perms-- Specification of Letters Patent.

Application filed February 28, 1907.

Patented. Dec. 15, 1908.

Serial l lo, 359,854.

nent and therefore introduced more resistonce than was (lGSllltDlB, and at tunes when foreign mutter was present, introduced "very objectionable resistance.

addition, specinl means had to beprovided for handling the cntho ing them to n instance for cleonsing.

de plates uni removaccount of the required.

greater space which it All the foregoing objections are removed in my present apparatus, and furthermore in the process OiLITlQd' out thereby, the tank for holding the electrolyte is thorou hly cleansed it the end of each detinning cycle shine and droppings removed therefrom and and all the the electrolyt c, together with the-matter contained therein, is subjected to such action that all solid foreign matter is removed from the electrolyte, so that it returns to the tank in a clear condition as distinguished from the otherwise muddy condition.

Furthermore whenever the tank descend Furthermore,

the cathodes in 'my apparatus are so constructed us to ellord u very large suri'ace for deposition, resulting in a very low amperage density, such as isdesirnble in on e lvtic detinning apparatus.

the conveyor is so constructed that the scrapectro- Furthermore,

does not bind between the conveyor bars and the basket, as is found to be the case when the conveyor bars the basket.

fill the passage through l urtherinorr I have devised means whereby the czwbonating 0f the electrolyte is very much lessened, th usthe frequency of regenerating the electrolyte is very much reduced. I have discovered that this latter result may be brou ht about byeliniineting alll wnterfells in 1; 1e circulation systern and thus preventing the entraining ofair and he curbonic acid whic Emmi-moron h is necessarily J i. tne relation owing is a clesiiripti gp of my invenbein [18. t0 1. 6 m I which 6 a CO pally 's side elevation of the a pathe tank lowered, the side 0 the tan being partly broken away. Fig. 2 is a view of the apparatus of Fig. 1, partly in front elevation. and partly in section. Fig. 3 a horizontal section on the line X X of Fig. 2 slig itly enlarged. Fi 4 is an enlarged (letail view cf the central cathode plates and scrapers. Fig. 5 is enlarged detail view of a portion of the outside cathode plates and scrapers. 6 is a sectional view showing of the cathode plates and scrapers. Figs. .7, 8, 9 and are detail views of the conveyor chain.

Referring more particularly to the drawings: 1 is a stationary metallic basket having that portion which is within the electrolyte perforated sides.- 1 is a hinged door for charging the basket. The basket is supported by U-beams 2, 2, which rest upon the flooring 8. Within the basket isaconveyer chain 4, made up of links 5,5, 5", 5, which move in grooves 6 formed in off-sets 7. The links 5 and 5 are of the shape-shown at 5" in Fig. 9. The link 5 is the same as 5 with the addition of an expanded portion lying in the same plane as the link 5. This expanded portion cooperates with the link 5, both-of which have abutting surfaces concentric with the pivots, so as to form a continuous cover for the slot 7. The ivots connecting these links carry rollers 7 for reducing the friction as the chains pass around the curve 8 at the lower portion of the basket. The grooves 7 are provided at the curves with raised tracks 8 forming grooves into'which enter the body portions of the links, as. shown in Fi 9. Cross-bars 4 are provided occupying about one-third of the width of the basket. With these proportions there is less liability to clog than when the cross-bars are substantially the full w dth of the basket. The con-.

veyer'chains pass over pulleys 9, 10 and 11 at each side of the conveyer, the driving power being applied to the pulley 9, which is provided with. sprocket teeth to engage the chain. The sprocket 9 is driven by a worm wheel 9 and a worm 12 mounted on a shaft provided with a bevel gear 12 driven by the bevel gear 12* on the shaft of the wheel 13, which. wheel is driven by the chain 14, assing over a sprocket 15 on the shaft of the driving pulley 16.

The basket is provided with four off-sets 17, 18. The oil-sets 18 are electrically connected to a conductor 19, the contacting surfaces being preferably brazed together. The cross-bars are secured to the conductor 19 by olts 20 and separated therefrom by insulation 21 and are brazed at. their other ends to the conductor 22, which is separated from set 17 and the basket by-insul'ation the and the front and rear sides are both covered with the deposited matter. A thirdcrossbar is located between the two portions of the basket and is electrically connected with the conductor 22 and is secured to and electrically insulated from the conductor 19 in the'samemanner as is the .bar 20. This bar also carries plates 24 which are similar to the other plates 24., except that they are of less length, since they cannot extend to, the bottom of the tank being within the turn or bend of the basket.

26 is a tank for the electrolyte which is sup orted by a hydraulic piston 27 working Wit in the cylinder 28. This hydraulic piston has a packing 29 and at its upper a collar 30 bolted to the flange 31. This collar 30 is a split collar, the two ends of which can be brought together by the screw 32. This permits the lunger 27 to. be clamped so as to be readi y held in either its upper position or its lower position for purposes hereinafter described. The tank 26 is separated from the plunger by insulation 33,

' so as to prevent short-circuiting. The tank is provided with an overflow 34 and with inlet and outlet pi cs 35, 36, and means 37 for heating the e ectrolyte and a pump 38 for causing it to circulate. The mouth of the inlet .35 opens beneath the level of the electrolyte when the tank 26 is raised to the position shown in dotted lines in Fig. 1 and in use and thus prevents a waterfall and the entraining of air and carbonic acid gas. To the upper flange of the tank are secured three scrapers consisting of bars 89, 39 carrying scraping blades 40 bolted thereto by bolts 41.

These scraping blades embrace the plates 24 of the cathode and as'the tank is lowcred scrape the cathode surface and remove the deposited matter-therefrom. A similar scraper having a bar 39 is provided for the central plates 24, but inasmuch as these plates are of less length than. the length of the outside plates 24 and it is not possible to have the scraper bar 39 move the same distance as the scra er bars 39, I provide meansfor permitting ost motion. These means consist of two rods 42 depending from the central cross-bar 25 and carrying stops 43. Thesestops limit the downward motlon of the scraper bar 39. The scraper bar 39 is provideeLwith depending rods 44 which pass coarse through the flanges of the tank and through stop &5, being provided at their lower ends heads l/Vith this construction, there is lost motion present, the result being that while the tank in its lowering movement will pull the cross-bar 39 down to the stops the crossbar 39 will rest at that point.

The cylinder 28 is connected with an acstimulator 4}, which has a ram of the same dime ens the ram 27 and carries a Weight itlpvhich less than the weight on the tank W on filled with electrolyte and greater than no weight of the tank when emptied, When the full tank is lowered, its Weight automat ically l the accumulator weight 48, being permitted to do so by the unclampingof the collar'SO. fx'hen the tank has reached its lowermost position, the collar 30 is again clamped while the electrolyte is removed. When the collar 30 is again released, the accumulator 48 will force the empty tank up- Ward into its normal position.

The cross-bar is fastened to the conduc= tor 19 by bolts which pass through insulation 20 so that the cross-bars are insulated from the tank. The cross-bars 39 and 39 are separated from the tank and the rods 44 by similar insulation and are, therefore, insulated from the tank. The rods 42 are held at their lower ends by anns 42 ,insulation 42* being interposed so as to insulate the rods 42 from the basket, this being necessary because they are electrically connected to the cross bars and to the scraper 39.

in operating the apparatus, startin with the parts in the positions shown in igs. 1 and 2, the clamping ring is first loosened, whereupon the accumulator Weight 48 forces the piston 27 carrying the now empty tank as upward into the position shown in dotted lines, Fi l. The clamping ring 30 is then tightened so as to hold the tank in raised position. The tank is then filled With the elec trolyte, the same being introduced by the pipe 35. Scrap is then introduced in the U-shaped basket throu h the door 1. It

may be shoveled in as ast as the conveyor moves, or may be shovele'd at intervals somewhat faster so as to fill the space inside of the door, which then can be closed so as to be held by its latch until more is needed. When scrap has been supplied, the current is switched on, the positive lead being connectoil to the basket 1 and the negatwe to the UlbllOdQ plates 24, and detinnlng begins as described in my previously mentioned application, the conveyor causing a substantially continuous mass of scrap'to pass through the stationary basket. After the cathode plates 24 are suilicicntly coatedwith'tin, the conveg-er is stopped and the current switched oil. The clam ing ring is then loosened with the result t at the tank "descends lifting the accumulator plunger and, weight 48. When the tank 26 has reached lowermost the caustic so powder and slime. The tin powder is scraped from the cathode plates 24% by the scra. ers 40 as the tank descends and falls direct y into the electrolyte. -The electrolyte,

together with the tin powder and slime is conveyed to a clarifying apparatus, preferably a centrifugal filter (not shown), where the solid matter is removed from the liquid. This operation not only ren'ioves the tin powder and slime but also removes the soap which is formed in the detinning bath an y hydrocarbons are introduced therein with the sore. to be detinned. After the electrolyte has con femoved from the tank, the'clelnping ring 30 is again loosened arid the tank ah lowed to ascend under-tho actii'm of the accumulator to its uppermost position Where it is again clamped. lt is again filled with the purified electrolyte and the conveyor started and the current switched on.

Throughout the detinning operation the electrolyte which is within the tank is kept in circulation, and isalso kept heated by the means of the circulating system, consisting of the pipes 35 and 36, the heater and the pum 38. The mouth of the pipe 35 de scen s enough so that i t is always just below i the surface of the dctinning bath during the circulation period. This prevents the formation of any waterfalls andthe consequent ,entraining of air and carbonh acid gas. By thus preventin the entraining of carbonic acid gas the life of the electrolyte. is very much lengthened, because it becomes carbonated less uicldy. In order to prevent ila from becomingl'atigucd by reason of the carbonating that necessarily takes place, 1 preferably withdraw a portion of it from time to time, and after regenerate in it, return it to the system.

' hen the tank 26 is lowered the basket and cathode should be carclully examined so as to see that no Wires or other metallic bodies protrude from the basket so as to make contact with the cathode and thus form short circuits. The tin scrai which lodges in the U of the basket should also be removed at this time. Thesysteni should preferably be kept in continuous operation day in and day out, and it is an advantage to have several detinning baths, or enough to keep one gang of men fairly busy in lower' ing 'andraising the tanks and removing the accumulated tin powder from the electrolyte, 'sincewhen the tanks are raised and the current turned on they re uire but little attentio11, the greater part oi the laborbeing that required to recover the tinpowder and remove the slime etc. from the electrolyte.

.As before pointed out all the electrical connections between the basket, cathodes o and conductors are permanent, and by rea son of having the basket and cathodes relatively stationary the basket\can be made much shorter. The basket and cathode plates can be inspected in all partsxand thc tin powder, which may lodge on the basket, can be removed. ln the old form of apparatus some tin powder would unavoidably drop into the electrolyte, and since there was no practical way of removing it, could not be recovered. soap and mud, so much so as often times to become quite thick and very dirty. By the present arrangement the electrolyte being requently filtered, is kept in a condition of high efiiciency. The system is provided with automatic scrapers. The particular scraper shown and described is simple and efficient. The plates are subdivided so as to permit a deposit of substantial uniform depth on both sides. The discharge of the suction pump of the circulating system enters the eating tank near its bottom and forces the from the bath into the bottom of the heating boiler, and up to a level slightly above the desired level of the electrolyte in the bath so that it flows by gravity with a gentle flow to the bath. The mouth of the suction pipe, which is within the detinning bath, is near the bottom of the tank when in elevated position. When the pump is in operation, the effect is to draw the electrolyte from the baths near the bottom where it is coolest, and force it into the heating boiler to a height above the level in the bath so that it flows out into the baths by its. owr head. It leaves the heating boiler without entraining air, as the mouth of thereturn'pi e is below the surface therein, and delivers te lye into the bath below the surface so as not to drive in any air at that point. The lye with this arrangement becomes carbonated much more slowly than is the case in systems where the circulation takes place with one or more waterfalls. The inlet and outlet pipe of the circulating system are, of course, shut oil by valves while the tank is lowered.

The improved method whereby carbonating is diminished is'claimed in a pending application No. 453,876, filed September 19, 1908.

What I claim is:

1. In a detinning apparatus, the combina' tion of one element consisting of a cathode and an anode relatively stationary, asecond element consisting of a tank for the electrolyte, means for raising and lowering one of said elements and a scraper for said cathode connected to said tank.

2. In detinning apparatus, the combinalyev drawn The baths became full of slime,

tion of one element consisting of a cathode and an anode relatively stationary, a second element consisting of a tank for the electro lvte, means for raising and lowering one of said elements, and a scraper for said cathode moving with said tank-and connected thereto so as to permit lost motion.

3. In a detinning apparatus, the combination of a cathode, an anode, a tank for the electrolyte, a hydraulic plunger for lowering and raising said tank, and an accumulator connected with the cylinder of said plunger, said accumulator being overcome by the weight of said tank when full and overcom ing the weight of said tank when empty.

4. In a detinning apparatus, the combina- 30 tion of a cathode, an anode, a, tank for the electrolyte, a hydraulic plunger for lowering and raising said tank, an accumulator connected with the cylinder of said plunger, said accumulator being overcome by the weight of said tank when full and overcoming the weight of said tank when empty, and means for restraining and releasing said tank.

5. In an electrolytic detinning bath, the

combination of a tank, an anode having a flat surface, a series of cathode plates lying in one plane and parallel to said surface the width of said plate being such as to make the resistance of the electrolyte between a point on the anode and all points on any one of said cathode plates approximately equal.

6. In an electrolytic detinning bath, the combination of a tank, an anode having a w flat surface, a plurality of series of cathode plates carried from a common support, said several series being parallel to each other the plates of each series lying in the same plane and being of such width as to make the re sistance of the electrolyte between a point on i the anode and'all points on any one of said cathode plates approximately equal.

7. In an electrolytic detinning bath, the combination of a tank, an anode, a flat cathode, a scraper engaging said cathode and. stationary relatively to said tank, said cathode and said tank being relatively movable along a line normal to the surface of the electrolyte.

8. In an electrolytic detinning a paratus, the combination of a tank, a plura ity of series of plates within said tank forming a cathode, horizontal scrapers normally located near the top of and engaging the flat surfaces of said cathode plates, and means for raising and lowering said tank and 129 scrapers.

9. In a detinning apparatus the combination of a stationary U-s'haped basket having internal grooves egrtenuing along the sides thereof, a convey'r within said basket having chains travelin in said grooves and antifriction rollers carried by said chains and en"- gaging said grooves.

10. In a detinning apparatus, the combination if a'statlonary U-shaped basket hav- 130 ing internal grooves extending along the sides thereof, a conveyor within said basket having chains traveling in said grooves and antifriction rollers carried by said chains and engaging said grooves, said-chains having in ner surfaces Wider than said grooves 11. In a caustic soda electrolytic apparatus, the combination of a plurality of vessels, a tin bearing anode and a cathode in one of said vessels, at source of current having its positive and negative leads connected to said anode and cathode respectively, feeding and return pipes for causing caustic soda to circulate Withinnnd discharge into said vessels, the discharge mouths of said pipes being covered by the electrolyte in the vessels into which they discharge. I

12. In a caustic soda electrolytic apparatus, the combination of a plurality of vessels, a tin bearing anode and a cathode in one of said vessels, a source of current having its positive and negative leads connected to and cathode being located near the imliOlll of said vessel.

13. lo a (it inning apparatus, the combination of a stiitii iaizy U-$llftPCl lmshol. having internal grooves extending along the curved port said grooves, and sntidriction rollers carried by said chains suid engaging said grooves, said grooves having inward projections engaged by said mitiiriction rollers.

Witnesses: V

HARRY .li. SODEN, Di'ieNi-n' lnnron.

on thereof, chains traveling in 

